minutes and died bef ore medical help could be obtained. No reliance can be placed on
receiving advance warning which might allow treatme nt to be had in time.
Heptachlor, one of the cons tituents of chlordane, is marketed as a s eparate formulation. It has
a particularly high capacity for storage in fat. If the diet contains as little as of 1 part per million
there will be measurable amounts of he ptachlor in the body. I t als o has the curious ability to
unde rgo change into a chemically dis tinct s ubs tance known as heptachlor epoxide. It does this
in s oil and in the tis s ues of both plants and animals. Tes ts on birds indicate that the epoxide
that results from this change is more toxic than the original chemical, which in turn is four times
as toxic as chlordane. As long ago as the mid-1930s a s pecial group of hydrocarbons , the
chlorinated naphthalenes , was found to caus e hepatitis, and also a rare and almost invariably
fatal liver disease in persons subjected to occupational exposure. They have led to illness and
death of worke rs in electrical indus tries ; and more rece ntly, in agriculture, they have been
cons idered a caus e of a mys terious and usually fatal disease of cattle. In view of these
antecedents , it is not s urpris ing that three of the ins ecticides that are related to this group are
among the mos t violently pois onous of all the hy drocarbons. These are dieldrin, aldrin, and
endrin. Dieldri n, name d for a German che mis t, Diels , is about 5 times as toxic as DDT when
swallowed but 40 times as toxic when abs orbed through the s kin in s olution. It is notorious for
s triking quickly and with terrible effect at the nervous s ys tem, s ending the victims into
convuls ions. Pers ons thus pois oned recove r s o s lowly as to indicate chronic effects. As with
othe r chlorinated hydrocarbons , thes e long-term effects include severe damage to the liver.
The long duration of its residues and the effective insecticidal action make dieldrin one of the
mos t us ed ins ecticides today, des pite the appalling destruction of wildlife that has followed its
us e. As tes ted on quail and pheas ants , it has proved to be about 40 to 50 times as toxic as DDT.
There are vast gaps in our knowledge of how dieldrin is s tored or dis tribute d in the body, or
excreted, for the chemists’ ingenuity in devising insecticides has long ago outrun biological
knowledge of the way thes e pois ons affect the living organism. However, there is every
indication of long s torage in the human body, where de pos its may lie dormant like a s lumbering
volcano, only to flare up in periods of phys iological s tres s when the body draws upon its fat
reserves. Much of what we do know has been learned through hard experience in the
antimalarial campaigns carried out by the World Health Organization. As soon as dieldrin was
substituted for DDT in malaria-control work (because the malaria mosquitoes had bec ome
res is tant to DDT), cas es of pois oning among the s praymen began to occur. The seizures were
severe—from half to all (varying in the different programs) of the men affected went into
convuls ions and s everal died. Some had convuls ions as long as four months after the las t
expos ure.
Aldrin is a s omewhat mys terious s ubs tance, for although it exists as a separate entity it bears
the relation of alter ego to dieldrin. W hen carrots are taken f rom a bed treated with aldrin they
are found to contain res idues of dieldrin. This change occurs in living tissues and also in soil.
Such alchemis tic trans formations have led to many e rroneous reports , for if a chemis t, knowing
aldrin has been applied, tes ts for it he will be deceived into thinki ng all residues have been
dis sipated. The res idues are there, but they are dieldri n and this requi res a different test. L i ke
dieldrin, aldrin is extremely toxic. It produces degenerative changes in the liver and kidneys. A
quantity the s ize of an as pirin tablet is enough to kill more than 400 quail. Many cas es of human
pois onings are on record, mos t of the m in connection with indus trial handling. Aldrin, like most
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